CPU is overclocked to 4Ghz, I don't know why this would start happening now as this has not been an issue until a few days ago. Should I try and disable HT? I know I have seen some people do that for BF3.

There has been a bug discovered with IE9 and hardware acceleration, it might be worth disabling any hardware acceleration in Firefox if there is any to see if there is an improvement.

The bug was discovered by our BF3 server provider:

Quote:

This is unrelated to the server side but we thought this should be mentioned as it's particular relevant to BF3 and Battlelog. This bug has been forwarded to DICE.

IE9 coupled with the latest Nvidia drivers (285.62) includes a GPU accelerator function that reserves a certain amount of rending power just for IE9 tasks that never gets released to other processes. I believe the beta drivers also included this.

While IE9 is open, for example Battlelog, single GPU performance is hit by up to 20% while in-game. SLI performance is more pronounced and gets hit by up to 50%. The impact is not immediate, it can take up to 2 hours (oddly) to take affect after a clean restart of Windows.

As far as we can see, this bug/function has not been documented and is on by default in IE9: Internet Options > Advanced > Accelerated Graphics. To disable, just tick 'Use Software rending instead of GPU rendering*'

I checked firefox and saw that hardware acceleration was not enabled and to be sure it was not the browser I installed google chrome and the issue still persists. I am going to try and install the latest drivers again and see if that helps.